Search results for " relativity"
showing 10 items of 1158 documents
Hochschild Cohomology Theories in White Noise Analysis
2008
We show that the continuous Hochschild cohomology and the differential Hochschild cohomology of the Hida test algebra endowed with the normalized Wick product are the same.
Radiative 2D Shocks, Super-Eddington Disks and Jets around Black Holes
2005
It is well known that rotating inviscid accretion flows with adequate injection parameters around black holes could form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. Such shock waves in 2D accretion flows are examined by 2D radiation hydrodynamical calculations. We also examine super‐Eddington accretion disks with 15 ṀE around black holes, focusing on a small collimation degree of the jet and a large mass‐outflow rate observed in the X‐ray source SS 433.
Radio mode feedback: Does relativity matter?
2017
Radio mode feedback, associated with the propagation of powerful outflows in active galaxies, is a crucial ingredient in galaxy evolution. Extragalactic jets are well collimated and relativistic, both in terms of thermodynamics and kinematics. They generate strong shocks in the ambient medium, associated with observed hotspots, and carve cavities that are filled with the shocked jet flow. In this Letter, we compare the pressure evolution in the hotspot and the cavity generated by relativistic and classical jets. Our results show that the classical approach underestimates the cavity pressure by a factor larger or equal to 2 for a given shocked volume during the whole active phase. The tensio…
Practical formula for the evaluation of high-order multiphoton absorption in thin nonlinear media
2009
We present an analytical formula for the fast and accurate evaluation of nonlinear absorption in materials exhibiting an admixture of different multiphoton processes. This approach is specifically addressed for its use in thin films when the slowly varying envelope approximation applies. The contribution of absorptions of distinct order is conveniently averaged in order to use well-known expressions for a single multiphoton process. In the latter case, therefore, our simple expression is reduced toward the exact solution.
A "imunidade soberana" de Pinochet contestada
2000
Um observador privilegiado e participante do processo que levou à quebra da "imunidade soberana" do ex-ditador chileno Augusto Pinochet expõe como e em nome do que isso ocorreu. A privileged observer of, as well as a participant in, the process that resulted in the breaking of the "sovereign immunity" of Chiles former dictator Augusto Pinochet tells how and in the name of what this happened.
Coxeter on People and Polytopes
2004
H. S. M. Coxeter, known to his friends as Donald, was not only a remarkable mathematician. He also enriched our historical understanding of how classical geometry helped inspire what has sometimes been called the nineteenth-century’s non-Euclidean revolution (Fig. 35.1). Coxeter was no revolutionary, and the non-Euclidean revolution was already part of history by the time he arrived on the scene. What he did experience was the dramatic aftershock in physics. Countless popular and semi-popular books were written during the early 1920s expounding the new theory of space and time propounded in Einstein’s general theory of relativity. General relativity and subsequent efforts to unite gravitati…
Anderson localization problem: An exact solution for 2-D anisotropic systems
2007
Our previous results [J.Phys.: Condens. Matter 14 (2002) 13777] dealing with the analytical solution of the two-dimensional (2-D) Anderson localization problem due to disorder is generalized for anisotropic systems (two different hopping matrix elements in transverse directions). We discuss the mathematical nature of the metal-insulator phase transition which occurs in the 2-D case, in contrast to the 1-D case, where such a phase transition does not occur. In anisotropic systems two localization lengths arise instead of one length only.
Slow-light solitons
2007
We investigate propagation of slow-light solitons in atomic media described by the nonlinear � -model. Under a physical assumption, appropriate to the slow light propagation, we reduce the � -scheme to a simplified nonlinear model, which is also relevant to 2D dilatonic gravity. Exact solutions describing various regimes of stopping slow-light solitons can then be readily derived.
Winteler, Jost (1846–1929)
2006
J Winteler was born in a village in the Swiss canton of Glarus. He studied philology in Jena, Germany. In his famous doctoral thesis, published in 1876, he described his native dialect of Kerenz. By analyzing the activity of the organs producing language (dialect) sounds, he was the founder of the so-called sound physiology (together with his teacher Eduard Sievers). In his prestructural approach, he noticed that there are sounds with and others without the capacity to change meaning. Purely structural terms were used already, such as Lautgegensatze (‘contrasts of sound’), (Sprach-)Bau ‘(linguistic) structure,’ and Konsonantensystem, Sprachsystem ‘system of consonants, of language.’ There w…
Contour/Outline/Silhouette
2020
The contour is the locus at which the parts of opaque solid objects appear to form an edge because it corresponds for the viewer to the projection of the rim, namely the curve that divides the surfaces into visible and invisible parts. The rim between the visible front and the invisible rear side is projected onto the contour that is the envelope of all the curves of equal depth. Although the rim and the contour run into depth, they are distinct concepts that regard the object-centred and the viewer-centred description. The outline is the boundary of the surface delimited by the contour, which fills a spatial region. Rubin (1921) discovered the property that allows the contour and the outli…